Present day automotive catalytic converter devices comprise a multichannel substrate whose flow-through channels are coated with noble metal catalyst materials to convert the pollutant exhaust gases to harmless effluent.
The automotive catalytic converters generally comprise large, oval shaped ceramic substrate housed in a metal sleeve or can. The converters connect directly to a manifold exhaust pipe, and generally discharge the purified gases to a muffler.
Exhaust gases entering the catalytic converter unit from the manifold exhaust pipe are generally specifically directed in their flow. That is, the gas flow tends to concentrate down the middle portion of the ceramic substrate, thus substantially avoiding the outer one-third of the substrate. This is a result of the narrow exhaust pipe cross-section, that feeds directly into the larger cross-sectional area of the substrate. The gases from the smaller exhaust pipe do not have a chance to radially diffuse as they enter the converter, and thus most of the exhaust gases flow down the middle of the substrate.
The result of this non-uniform bathing of the converter substrate is not only inefficient, but seriously limits the operational life of the converter.
It is also customary in some catalytic converter systems to inject air into the longitudinal mid-portion of the converter for the purpose of reducing the oxides of nitrogen emissions that are present in the exhaust gases. This procedure is also an inefficient use of converter substrate, since only a downstream portion of the substrate is provided with the oxygen enriched effluent.
The present invention seeks to provide an apparatus at the inlet of the converter that will more uniformly bathe the converter substrate with exhaust gases. The apparatus also has as an additional purpose to introduce air into the exhaust gas ahead of the frontal substrate interface to provide a more efficient treatment of nitrogen oxides as well as provide uniform gas distribution to the substrate.
The catalytic converter accessory of this invention uses a dynamic air/exhaust or an exhaust/exhaust gas mixture that provides a swirling diffusion of gases at the exhaust pipe/converter interface.